// let a = {}
// let b = [1,2,3,4]
// let c = 123
// let d =function(){}
// let e = ()=>{}
// console.log(a.toString());//[object Object]
// console.log(b.toString());//1,2,3,4
// console.log(c.toString());//123
// console.log(d.toString());//function(){}
// console.log(e.toString());//()=>{}
// console.log(b.join());1,2,3,4
function Pre(){

}
let test = new Pre()
console.log(test.__proto__.__proto__.constructor);


console.log(Function.__proto__==Function.prototype);